137 lines
4.8 KiB
C
137 lines
4.8 KiB
C
/* hash.h --
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*
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* *********************************************************************
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* * Copyright (C) 1985, 1990 Regents of the University of California. *
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* * Permission to use, copy, modify, and distribute this *
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* * software and its documentation for any purpose and without *
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* * fee is hereby granted, provided that the above copyright *
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* * notice appear in all copies. The University of California *
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* * makes no representations about the suitability of this *
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* * software for any purpose. It is provided "as is" without *
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* * express or implied warranty. Export of this software outside *
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* * of the United States of America may require an export license. *
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* *********************************************************************
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*
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* This file contains definitions used by the hash module,
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* which maintains hash tables.
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*/
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/* rcsid "$Header: /usr/cvsroot/magic-8.0/utils/hash.h,v 1.2 2009/09/10 20:32:55 tim Exp $" */
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#ifndef _MAGIC__UTILS__HASH_H
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#define _MAGIC__UTILS__HASH_H
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/*---------------------------------------------------------
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* This first stuff should only be used internally
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* in the hash routines.
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*---------------------------------------------------------
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*/
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/* The following defines one entry in the hash table. */
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typedef struct h1
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{
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char *h_pointer; /* Pointer to anything. */
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struct h1 *h_next; /* Next element, zero for end. */
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union
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{
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const char *h_ptr; /* One-word key value to identify entry. */
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unsigned h_words[1]; /* N-word key value. Note: the actual
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* size may be longer if necessary to hold
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* the entire key.
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*/
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char h_name[4]; /* Text name of this entry. Note: the
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* actual size may be longer if necessary
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* to hold the whole string. This MUST be
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* the last entry in the structure!!!
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*/
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} h_key;
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} HashEntry;
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/* A hash table consists of an array of pointers to hash
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* lists:
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*/
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typedef struct h3
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{
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HashEntry **ht_table; /* Pointer to array of pointers. */
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int ht_size; /* Actual size of array. */
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int ht_nEntries; /* Number of entries in the table. */
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int ht_downShift; /* Shift count, used in hashing function. */
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int ht_mask; /* Used to select bits for hashing. */
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int ht_ptrKeys; /* See below */
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/* Used if ht_ptrKeys == HT_CLIENTKEYS */
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char *(*ht_copyFn)(); /* Used for copying a key value */
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int (*ht_compareFn)(); /* Used for comparing two keys for equality */
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int (*ht_hashFn)(); /* Hash function */
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int (*ht_killFn)(); /* Used to kill an entry */
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} HashTable;
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/*
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* Values for ht_ptrKeys.
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*
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* HT_STRINGKEYS means that keys are NULL-terminated strings stored
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* in the variable-sized array h_key.h_name at the end of a HashEntry.
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*
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* HT_WORDKEYS and HT_CLIENTKEYS both mean that the value is stored
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* in h_key.h_ptr; with HT_WORDKEYS it is treated as a one-word value,
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* while with HT_CLIENTKEYS it is interpreted by user-supplied procedures
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* (and hence it can be a pointer).
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*
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* Finally, values of ht_ptrKeys of HT_STRUCTKEYS or greater mean
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* that the key consists of ht_ptrKeys 32-bit words of data, stored
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* in the variable-sized array h_key.h_words.
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*/
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#define HT_CLIENTKEYS -1
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#define HT_STRINGKEYS 0
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#define HT_WORDKEYS 1
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#define HT_STRUCTKEYS 2
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/*
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* Default initial size (number of buckets) in a hash table.
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* May be passed to HashInit() or HashInitClient().
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*/
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#define HT_DEFAULTSIZE 32
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/* The following structure is used by the searching routines
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* to record where we are in the search.
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*/
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typedef struct h2
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{
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int hs_nextIndex; /* Next bucket to check (after current). */
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HashEntry * hs_h; /* Next entry to check in current bucket. */
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} HashSearch;
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/*---------------------------------------------------------
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* The following procedure declarations and macros
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* are the only things that should be needed outside
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* the implementation code.
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*---------------------------------------------------------
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*/
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extern void HashInit(HashTable *, int, int), HashInitClient(), HashStats(), HashKill(),
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HashFreeKill();
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extern HashEntry *HashFind(HashTable *, const char *);
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extern HashEntry *HashLookOnly(HashTable *, const char *);
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extern void HashRemove(HashTable *, const char *);
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extern void HashStartSearch(HashSearch *);
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extern HashEntry *HashNext(HashTable *, HashSearch *);
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/* char * HashGetValue(h); HashEntry *h; */
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#define HashGetValue(h) ((h)->h_pointer)
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/* HashSetValue(h, val); HashEntry *h; char *val; */
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#define HashSetValue(h, val) ((h)->h_pointer = (char *) (val))
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/* HashSize(n) returns the number of words in an object of n bytes */
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#define HashSize(n) (((n) + sizeof (unsigned) - 1) / sizeof (unsigned))
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/* HashGetNumEntries(ht); HashTable *ht ; returns number of entries in table */
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#define HashGetNumEntries(ht) ((ht)->ht_nEntries)
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#endif /* _MAGIC__UTILS__HASH_H */
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